The present invention pertains to removable weatherproof covers for railroad coil cars and the like.
In recent years it has become common for railroad companies to provide removable covers for certain types of otherwise open cars, in order to protect their cargo from the elements and to reduce damage claims. One example is a type of car known generally as a coil flat car, which is a special type of flat car having a shallow cradle and which is adapted for carrying large cylindrical coils of cable, sheet metal, aluminum and the like.
Covers for these cars have heretofore been made of steel, from large plates or sheets of sheet metal welded together with a few angle iron braces and beams to form the generally box shaped, open bottomed cover which is adapted to fit down over the coil car. A crane hook point is provided at the top, and a plurality of stacking shelves are often provided near the top for receiving the base of another cover, in stacked position.
The resulting prior art structure has proved to be less than satisfactory in a number of respects. For one thing, a single cover made of steel weighs approximately 3,000 pounds. Considering that two covers are generally required for each coil car, this represents three tons of deadweight per car, and represents a considerable extra expenditure of fuel for hauling this additional weight from point of origin to the destination.
A second disadvantage stems from the vulnerability of the steel covers to damage during handling by the lifting crane. The previously mentioned structure of sheet metal welded with angle iron reinforcing brackets is inherently subject to popping loose at the seams when a corner or side of the cover is bumped against another structure. This type of damage is encountered on a very frequent basis during lifting of the cover from a car, stacking one cover on another, and the reverse process. Also, the steel covers are inherently subject to rusting.
Another disadvantage of steel prior art covers is their poor thermal characteristics. Since steel is inherently a good thermal conductor, cool air in contact with the outside of the cover may cause condensation on the inside of the car and the cargo, leading to rusting both of the cover and the cargo. Insulation spray coatings have been applied on the insides of steel covers to solve this problem, but this additional process greatly increases the cost of the cover.
The present invention overcomes these and other problems existing with the present state of the art steel car covers. Car covers according to the present invention are made of fiberglass reinforced plastic (FRP). The resulting structure is almost as strong as steel, but weighs only about 1,500 pounds per cover. This results in a substantial savings in deadweight for the railroad, giving corresponding savings in fuel, greater available cargo load per car, and greater flexibility in balancing the load.
Covers according to the present invention are inherently more resistant to damage and breakage during normal handling than are the steel covers of the prior art. Fiberglass reinforced plastic is inherently more resilient in forgiving of bumps and rough handling, and will not dent or chip off paint and begin to rust. Since the main body of the cover is made as a single integral shell, there are no corner seams to split, leak or pop open if the cover is bumped or dropped on a corner.
Finally, since the FRP structure is inherently a better heat insulator than steel, the condensation problem referred to above is greatly alleviated in the present invention, without the necessity of additional expensive insulation coatings.